1. Field of the Invention (Technical Field)
The present invention relates to aperture shutters, particularly to fast mechanical shutters, and specifically to an apparatus and method for realizing regulated, ultra-fast, opening and closing of a system aperture.
2. Background Art
There was for some time a need in the arts of both still photography and motion-picture making to provide shutter devices for the rapid opening and closing of a camera aperture for the purpose of exposing the film. Increased technological sophistication in the movie making art, in particular, has resulted in the improvisation of a number of optical shutter devices. Representative patents in this field include U.S. Pat. No. 3,735,687 to Park, U.S. Pat. No. 4,301,476 to Keller et al., U.S. Pat. No. 4,536,069 to Kunica, U.S. Pat. No. 4,571,629 to Horio et al., U.S. Pat. No. 4,581,515 to Egashira, U.S. Pat. No. 4,576,456 to Okino et al., U.S. Pat. No. 4,743,108 to Vogel et al., U.S. Pat. No. 5,539,488 to Erickson et al., and U.S. Pat. No. 5,850,277 to Dang et al.
More recently, a need has arisen for fast shutters for use in protecting diagnostic and sensing equipment in certain testing systems. For instance, in various research systems, it is required to measure the energy effects of a physical blast event. In certain types of research, a defined target may be bombarded with selected energy beams, or may be deliberately subjected to explosion. It is desirable in many cases to measure and evaluate the energy emanating from the target area. Measurement and evaluation often must be accomplished using sensitive and sometimes somewhat fragile yet expensive detection devices. In such instances, it is essential to protect the detection/measuring devices from physical blast debris originating from the target area as a result of the high-energy experiment. High-velocity particulate debris may damage or destroy sensitive detection or measurement instruments.
To protect delicate instrumentation in such experimental and testing systems, it is known to place some sort of barrier between the instrument and the target or blast zone, and to provide an aperture in the barrier to permit measurement by the detection device. A shutter is used to open the aperture at appropriate times to permit the passage of the energy to be measured, and then immediately closed prior to the passage of the ensuing wave of physical debris. The paramount challenge of such shuttered systems is the provision of sufficient shutter speed to allow the desired measurement to take place, and yet also prevent the passage of deleterious physical debris.
Currently, the protection of delicate detection devices in such experimental and testing systems often is accomplished by the simple expedient of widely separating the measurement instrumentation and the target zone. This solution is based upon the presumption that the energy to be measured (typically in the form of electromagnetic energy, or sub-atomic particles at near-light velocity) will rapidly out-distance, over relatively long distances, comparatively slow-moving microscopic or small macroscopic debris particles. Drawbacks of this solution include the larger size of the system, and the undesirable attenuation of the effect to be measured.
It has also been proposed to construct a fast shutter that is itself actuated by a chemical explosion. In such systems, a timed explosion drives a shutter (usually mechanical) closed at high speed. One example of such a detonator-activated shutter is described in U.S. Pat. No. 4,398,801 to McWilliams et al. While very fast-acting, such explosive-driven shutters pose obvious disadvantages.
A need remains, therefore, for a compact, energy-efficient, ultra-fast shutter suitable for use in protecting diagnostic and measuring instruments from deleterious blast debris in high-energy tests and experiments, and which allows the instruments to be situated proximate to the target area.